Internet down for several hours during the work week

Just switched from ATT to Comcast a month ago. First couple weeks were great, but recently our internet has been completely dropping for several hours during the week. On friday, 4/24, the internet was down for 6 hours from 3pm-9pm. Today (Monday), it was off for over 8 hours from 9am to 6pm. Whats strange is that it works just fine on the weekends. We've called Comcast, and they've had us check connection, restart modem, etc (which doesn't solve the issue). Also had a tech visit where he checked the cable connections again, said they were fine and that he needed to send out "network specialist" instead. Never heard back and had to call and explain the whole situation again. They are sending another tech out tomorrow and I am afraid he is just going to do the same thing. The customer service rep on the phone said she was unable to give us a ticket number or address a past ticket. Is there something we're missing here? How do we ensure our issue is followed through with so we dont have to keep calling and being asked to simply restart our modem?